In connecting a rotary switch into a circuit, lead wires are typically connected to the terminals by crimping the wire around the terminal and then securing the wire with solder. In order to apply the solder to the joint, the terminal and wire are heated using a soldering iron and then the solder is brought into contact with the heated terminal. The heat retained by the terminal causes the solder to change into a liquid state and enables the solder to flow into cracks forming the joint. Flux is typically used during the soldering process to facilitate the flowing of the solder. When excess flux is used, a residue from the soldering process flows along the surface of the terminal and can enter the switch causing open circuit condition, namely, interruption of electrical current flow. In particular, the flux residue can develop as a thin resistive film on the surface of the collector plate within the switch. Because flux compounds are current limiting, traces of flux within the contacting area can render the switch inoperative.
Efforts have been made to avoid contamination of the switch internal parts by flux residues. This is typically accomplished by applying silicon or other sealing compounds to the openings in the switch housing through which the terminals extend. Gaskets have also been used between sections of the switch housing to form a seal. These methods of sealing the housing, however, increase the cost of the switch by added assembly labor, material and parts thus complicating manufacturing process.